3. Relative dates stay relative in the protocol

Status: accepted

Context

"Last 7 days" can be stored as absolute timestamps or as a relative expression. Absolute timestamps go stale, lose the user's intent, and make cached interpretations wrong the next day. Relative expressions need a timezone to mean anything.

Decision

Relative operators (last, next, today, thisWeek, …) are stored as-is, and the query carries context.timezone. resolveDates() converts them to absolute ranges at execution time, for backends that want them.

Consequences

• Queries stay semantic, shareable and cacheable (the cache key includes the calendar day for safety).
• Every executor must resolve dates the same way; the reference implementation and the conformance suite define that, including DST.
• The engine warns (TIMEZONE_DEFAULTED) when relative dates are resolved in an implicit UTC.